The grand daddy of them all - the audion invented by Lee de Forest in 1906 and developed by engineering staffs
[Image ID: 99555 from NYPL.org]

What was the best thing before sliced bread? * According to the Wiki, "... arguments still continue about whether De Forest really invented the triode vacuum tube. What is apparent is that he—and everybody else at the time—greatly underestimated the potential of his original device …."

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* Sliced bread was first sold in 1928.

Rohwedder's 1928 (filed) patent for the bread-slicing machine at left.

"De Forest was granted a patent for his early two-electrode version of the audion on November 13, 1906 (U.S. Patent 841,386) but the "triode" (three electrode) version was patented in 1908 (U.S. Patent 879,532).

"...
De Forest continued to claim that he developed the audion independently from John Ambrose Fleming's earlier research on the thermionic valve—for which he received Great Britain patent 24850 and the American Fleming valve patent U.S. Patent 803.684—and became embroiled in many radio-related patent disputes."

Apparently for De Forest the trouble with being first was that there was nobody to appreciate it. To add insult to what is looking more and more like self-inflicted injury, "De Forest was famous for saying that he ‘didn't know why it worked, it just did.’ He always referred to the vacuum triodes developed by other researchers as oscillaudions although there is no evidence that he had any significant input to their development…

"... In 1914 Edwin Armstrong published an explanation of the audion and when the two later faced each other in a dispute over the regeneration patent, Armstrong was able to demonstrate conclusively that De Forest still had no idea how it worked."